It's alright, stopped using points ages ago.
- Thread starter Rannsachair
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Rannsachair
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Was fettling the AJ today as it was struggling to get over 60 mph. Found retarding the ignition made a big difference, 75 with ease.
Rannsachair
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Decided to retime the engine a little retarded last night, started it this morning and got the tell tale frapping noise of a blown head gasket!
These engines have separate heads and barrels, so not too hard to strip:
Head gasket was blowing:
I cleaned up the head on a sheet of plate glass with Fine emery paper taped to it, could not measure a warp, I suspect the head was under torqued:
Lucky I had an unopened old gasket set:
Valve clearances is quite an ingenious design, slacken a small nut that retains a cam:
the cam:
so you just adjust the clearance with a screwdriver, really quick and easy:
Not all went to plan, someone had fitted a cycle nut to a BSF thread and the threads came apart as I tightened it on the Carb flange, so cut a bolt to make a new one:
Rebuilt in an afternoon, started first kick and sounds the best it has:
These engines have separate heads and barrels, so not too hard to strip:
Head gasket was blowing:
I cleaned up the head on a sheet of plate glass with Fine emery paper taped to it, could not measure a warp, I suspect the head was under torqued:
Lucky I had an unopened old gasket set:
Valve clearances is quite an ingenious design, slacken a small nut that retains a cam:
the cam:
so you just adjust the clearance with a screwdriver, really quick and easy:
Not all went to plan, someone had fitted a cycle nut to a BSF thread and the threads came apart as I tightened it on the Carb flange, so cut a bolt to make a new one:
Rebuilt in an afternoon, started first kick and sounds the best it has:
selectedgrub
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Nice ride
Rannsachair
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Aye, I am never really happy with an old bike until I have rebuilt it.
oldbikedavey
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Replacing those Thackeray washers with bronze spacers would cheer things up a bit in the valve gear friction department.....
Rannsachair
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I did trim the inlet manifold/head gaskets to not extend beyond the castings, that may have released more power.
oldbikedavey
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Incoming turbulence can be important in promoting flame - front propagation...
Rannsachair
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Yes, have seen that polishing ports is often not a good idea, though I recall drawing up inlet restrictors for Hinkley Triumph to restrict power.
Rannsachair
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Well I have now discovered to my cost the fibre head gasket I fitted has an awful torquing process. Tighten, leave overnight tighten again. Start and run for 10 mins leave to cool tighten. Run 100 miles tighten. 500 miles tighten then that should be it. So not doing that resulted in a blown head gasket again! Just sorted it with a solid copper gasket. So now looking at why my T120 is starting ok but dying when I open the throttle:
addjunkie
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If you got shot of all that old european junk, and bought modern jap, you could ride not fiddle on! Just an observation!
Rannsachair
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Where would be the fun in just doing that..... it would be like selling my Landrover and buying a Toyota
And I would just be out in the rain more.
addjunkie
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New Landcruiser might be a good option!Where would be the fun in just doing that..... it would be like selling my Landrover and buying a Toyota
And I would just be out in the rain more.
oldbikedavey
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I'd be inclined to do a spark energy test on the Bonnie. Should jump an 8 mm gap at atmospheric pressure .
dobbslc
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Fiddling time is enjoyable too.
Rannsachair
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Old fuel residue blocking carb jets was the problem, from a leaking tap, so new tap fitted and carbs cleaned:
Started after a few kicks
Unfortunately oil leaking past the points drive oil seal, so new one ordered.
Started after a few kicks
Unfortunately oil leaking past the points drive oil seal, so new one ordered.
oldbikedavey
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That's rather horrible - looking....
